University identifies critical 802.11 wireless flaw

A serious wireless network technology flaw that could lead to the breakdown of some critical infrastructures in just five seconds...

A serious wireless network technology flaw that could lead to the breakdown of some critical infrastructures in just five seconds has been identified by Queensland University of Technology's (QUT) Information Security Research Centre.

Wireless technology is gaining traction and in some countries is used to control infrastructures such as railway networks, energy transmission and other utilities.

QUT's School of Software Engineering and Data Communications deputy head, associate professor Mark Looi, said the discovery of the flaw should send a warning to high levels of government and industry worldwide.

"Any organisation that continues to use the standard wireless technology [IEEE 802.11b] to operate critical infrastructure could be considered negligent," Looi said.

"This wireless technology should not be used for any critical applications as the results could, potentially, be very serious."

Looi's PhD students - Christian Wullems, Kevin Tham and Jason Smith - discovered the flaw while investigating mechanisms for defending wireless devices against being hacked.

The findings are to be presented to the Institute of Electrical and Electronic Engineers (IEEE) Wireless Telecommunication Symposium in California tomorrow (14 May).

In effect, the flaw allows for the disruption of the standard 802.11b radio frequency developed by the IEEE to transmit data.

The result is that the wireless devices cannot communicate with each other and service is denied.

"The 802.11b network is supported by a number of computing platforms including Macs, PCs and handheld devices and in 99.9% of all cases is the only way to connect to wireless networks," Looi said.

"To exploit the vulnerability potential attackers only need a common wireless adaptor which retails for about £20 and instead of using it to enable their computer to access a network, they can change its coding to interfere with transmission.

"With this adaptor you can basically totally disrupt any wireless network that uses this technology within a kilometre of its operation in anywhere between five and eight seconds."

The Information Security Research Center at QUT has been working with Australia's national computer emergency response team AusCERT to alert manufacturers about vulnerable wireless networking equipment since the discovery was made last November. A solution to the problem is yet to be found.

Looi said it was important to release the findings to ensure that users of the wireless technologies were made fully aware of the potential risks to their systems. There are about 12 public access networks plus numerous corporate Intranet systems that could be affected, he added.

The process to bring down a wireless network was very simple, although it did not compromise the data on the network.

"When the adaptor is given the right sequence of codes, it sends out enough information over the air for the network link to mistake it as interference - when this happens all devices on the network delay their transmission for a short period of time," he said.

"The adaptor will keep sending out the interference signal so the wireless network can't resume its normal transmission," he said, adding that any computer, PDA or notebook could send out the signal if the wireless adaptor was programmed accordingly.

Tools are being developed so wireless networks can be tested to see how vulnerable they are to being disrupted in this way.

Sandra Rossi writes for Computerworld

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